Contemporary valves are used in a variety of applications to govern the flow a liquid or a gas, collectively referred to herein as a fluid. Although a particular valve design is largely dependent upon its application, a majority of valves typically include a housing that defines a flow path therethrough. A valve member is positioned within the flow path to selectively allow or prevent flow, or to govern the characteristics of flow through the valve.
Valves are often characterized by the type of valve member they incorporate. For example, a ball valve typically incorporates a spherical valve member. As another example, a butterfly valve typically incorporates a disc shaped valve member. Various other configurations are readily recognized in the art.
These valve members are typically actuated manually or automatically via a stem or the like. The stem extends from the valve member to an exterior of the valve housing. Movement of the stem results in a corresponding movement of the valve member, which ultimately dictates the flow through the valve along the flow path therethrough.
With this general construction in mind, several problems arise as a result of the valve member's position within the flow path. As one example, a particular flow path through a valve can have complex turns and bends as a result of the shape and position of the valve member within the housing. That is, the flow is not straight through the valve between an inlet and an outlet of the housing. As a result, there is an increased amount of undesirable turbulence in the flow through the valve.
As another example, the shape and placement of contemporary valve members can lead to a relatively high pressure differential across the valve, i.e. high valve back pressure. To cope with high valve back pressure, additional energy must be expended by a pump to maintain system pressure while moving the fluid through the system. Further, turbulent flow and/or high valve back pressure applications can lead to the undesirable necessity of more robust and higher cost flow sensors within the flow path to accurately sense flow through the valve.
As yet another example, the complex flow paths necessitated by various configurations of valve members can lead to an increased amount of noise due to the flow of fluid around such valve members. This is especially problematic in air flow applications such as duct work and the like.
In view of the above, there is a need in the art for a valve with a valve member that reduces or eliminates the need for a fluid to traverse complex flow paths when moving through a valve. The invention provides such a valve. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.